It is common in the dispensing arts to provide disposable units in which a pump is secured to a container that holds the product that is to be dispensed. Actuating the pump causes the product to be dispensed from the container, and, when the container is empty of product (or the product level is below the pump intake), the unit can be disposed of to be replaced with a new unit. While a multitude of products are dispensed in this manner, various products of particular interest in the present application include soaps and sanitizers, though this invention is not to be limited to or by any particular product to be dispensed.
In some dispensing systems, the combination pump and container are received in a dispenser housing, which provides the actuating mechanisms necessary to actuate the pump and cause the dispensing of product to the individual operating the dispensing system. A particular example is shown in FIGS. 1 and 2, which shows a wall-mounted dispenser 10. The dispenser 10 includes a dispenser housing 12 that is mounted to a wall and opens to receive a combination reciprocating piston pump 14 and container 16, the combination being herein referred to as a “refill unit,” which is designated by the numeral 18. In the embodiment shown, a pushbar 20 of the dispenser housing 12 interacts with the reciprocating piston pump 14 of the refill unit 18 such that pushing on the pushbar 20 (typically when the cover 21 of the dispenser housing 20 is closed) causes the reciprocating piston pump 14 to be actuated to dispense product at the outlet of the dispenser 10. This outlet might be provided at the end of a dispensing pathway provided by the pump 14, or might be a separate portion of the dispenser 10, with the dispensing pathway of the reciprocating piston pump 14 appropriately communicating therewith when the refill unit 18 is received in the housing 12. The dispenser housing and refill unit concept is all generally known and currently widely practiced in the dispensing arts, particularly for soaps, sanitizers and lotions and other personal care products.
A cross-section of a refill unit 18 is shown in FIG. 2. The reciprocating piston pump 14 fluidly communicates with a liquid S within the container 16, communicating through an inlet 22 of an axial extension 24 that extends adjacent a valve seat for an inlet valve 28. The inlet valve 28 helps to define a liquid chamber 26, the chamber being defined by the volume within a liquid pump sidewall 50 between the inlet valve 28 and an outlet valve 30. These valves 28, 30 ensure that the reciprocating piston pump 14 operates, upon proper actuation, to advance a dose of liquid S to the dispensing pathway 36 of the pump, ultimately advancing a dose of liquid to the end user, and after actuation and upon return to the rest state due to the spring 34, draws a dose of liquid from the container 16 into the liquid chamber 26.
A liquid piston 32 resides in the liquid chamber 26 and is biased by a spring 34 to a rest position, as shown in FIG. 2, wherein the liquid chamber 26 has an expanded volume, defined between the valves 28, 30 and the sidewall 50. Notably, the piston 32 is termed a “liquid” piston simply because it serves to pump liquid. To dispense product, the liquid piston 32 is moved against the bias of the spring 34 (upwardly in the orientation of FIG. 2) to an actuated position in which the liquid chamber has a compressed volume that is less than the expanded volume. The change in volume increases the pressure in the liquid chamber 26, causing the inlet valve 28 to close off communication with the interior of the container 16 at inlet 22. The increase in pressure causes the outlet valve 30 to open, and a portion of the liquid S in liquid chamber 26 exits to a dispensing pathway 36.
While the operation just disclosed with respect to the liquid chamber 26, valves 28, 30, spring 34 and the liquid piston 32 are sufficient for the dispensing of liquid S, it should also be appreciated that the reciprocating piston pump 14 can further include, as shown, an air chamber 38 and an air piston 40. The piston 40 is termed an “air” piston because is serves to pump air. The air piston 40 would move with the movement of the liquid piston 32 to compress the volume of the air chamber 38 to force air from the air chamber 38 into the dispensing pathway 36 where the air mixes with the liquid S to create a foam product. In such instances, the liquid S is a foamable liquid, and a screen or foaming chip 48 would be provided along the dispensing pathway 36 to facilitate the creation of foam. For example, a liquid soap produces a foam soap product when mixed in this manner, and some sterilizer formulations can also foam in this manner.
In dispensers such as wall-mounted dispensers 10, the reciprocating piston pump 14 is employed in an inverted position as shown in FIGS. 1 and 2, with the reciprocating piston pump 14 positioned partially in the neck 42 of the container 16 and held therein by an cap portion 45 threaded over the neck 42 of the container 16. The inlet 22 of the axial extension 24 extends well into the interior of the container 16, above an established floor of the container 16. As shown in FIG. 2, the reciprocating piston pump 14 might entirely fill in the neck 42, such that a floor 17 would be established at the bottom of the container 16, with the liquid S in the container 16 being able to reach that floor 17 in the inverted positioning of the container 16. Alternatively, as shown in FIG. 3, the reciprocating piston pump 14 may fit intimately in the neck 42 with its structure such that it provides a lowermost floor 29 (at the exterior sloped surface of the reciprocating piston pump 14) for the contents of the container 16. In such an instance, the pump itself would be considered as providing a floor for the liquid.
In the inverted positioning just described, once the level of liquid in the container 16 falls below the inlet 22 of the axial extension 24, subsequent actuation of the reciprocating piston pump 14 will not draw liquid from the container and into the liquid chamber 26, and much of the contents of the refill unit 18 will be wasted (or at least be incapable of being dispensed by further actuation of the inverted reciprocating piston pump 14). Particularly, that volume of liquid S existing between the inlet 22 and the floor of the container 16, whether of a type like floor 17 or floor 29 described above, will not be capable of being dispensed by further actuation of the inverted reciprocating piston pump 14. This leads to a significant waste of liquid S.
This problem has been addressed in the prior art by providing either a curved dip tube or an uptake shroud to redefine the inlet to the pump at a different, lower position than is established without them. In FIG. 3, a curved dip tube 44 fluidly communicates with inlet 22 and effectively provides the reciprocating piston pump 14 with an inlet 22b at a position much lower than that for inlet 22. Similarly, in FIG. 4, an uptake shroud 46 fluidly communicates with inlet 22 and effectively provides the reciprocating piston pump 14 with an inlet 22c at a position much lower than that for inlet 22.
A curved dip tube or uptake shroud in the pump design increases the complexity of the pump and the costs to manufacture it, particularly due to material costs and the additional manufacturing steps necessary to product and connect those structures.